Spindle clamp



5 1960 L. o. CARLSEN ETAL 2,947,061

SPINDLE CLAMP Original Filed Dec. 30, 1955 INVENTORS 26 25 LEONARD O.CARLSEN H62 By HERMAN A.MALE

ATTORNEY Fig. 1.

SPINDLE CLAMP H Leonard 0. Carlsen, Rochester, and Herman A. Male,

Brighton, N.Y., assignors to The Gleason Works, Rochester, N.Y., a corporation of New York Original application Dec. 30, 1955, Ser. N0. 556,725, now Patent No. 2,812,186, dated Nov. 5, 1957. Di-

vided and this application Jan. 18, 1957, Ser. No. 634,960

6 Claims. (c1. 29-1 United States a Patent I 2,947,061 Patented Aug. 2,1960

ice

15and thespindlehousing with a fluid-expansible tubular annulus16 fitting the groove. The grooveis formed betively. The expansible annulus has relatively thin and resilient side walls2 1and 22 respectively formed integrallylwith ring-shaped sections 23and 24 of the spindle According to one aspect of the invention a gear cutting.-

machine or the like comprises a spindle housing, a work 1 spindle journaled for rotation in hearings in the housing and having a workpiece-supporting end portion projecting beyond said bearings, said end portion of the spindle having an annular peripheral groove, and the housing having a fluid-expansible tubular annulus fitting in said groove, the opposite side walls of the annulus being adapted for relative displacement, axially of the spindle, to clamp against the opposite walls of the groove u'pon expansion of the annulus by fluid under pressure.

side walls adjacent the inner peripheries thereof to accommodate the relative axial displacement of their inner peripheral portions incident to such flexure.

' This arrangement, While adapted to clamping the spindle to the housing with enough pressure to overcome any tendency of the spindle to turn in the presence of heavy cutting loads applied to the workpiece, imposes little or no load on the spindle bearings, allows free rotation of the spindle when clamping pressure is released, and, aside from slight relative flexing of said side wall portions and their seal, has no relatively moving parts except the rotatable spindle itself.

The foregoing and other features of the invention will appear from the following description of the preferred embodiment illustrated in the accompanying drawings, wherein:

Fig. 1 is a side elevation of the front portion of a work spindle, with the workpiece carried thereby and the adjacent parts of the spindle housing appearing in vertical section; and,

Fig. 2 is atragmentary cross-section in plane 2-2 of As shown in 1 a work spindle 10 is mounted for rotation in a spindle housing. 11 on anti-friction bearings,

housing 11, which "sections are secured to the main section of the housing by screws 25 and 26 respectively. Preferably the sections 23 and 24 are made of steel and the parts 21 and 22 thereof are heat treated to provide the desired resilience. The side walls of the annulus have spaced overlapped flanges 27 and 28 between which is disposed a flexible O-ring seal 29. 'Fluid pressure is applied to the interior of the annulus through a passage 30 leadingfrom a source of pressure and control valve means (not shown) associated with the index mechanism of the machine, which includes a notched index plate (not shown) secured to the rear end of the spindle. The arrangement is such that when the index mechanism is not operating, i.e. when the workpiece is being cut, fluid pressure is applied through passage 30 to expand the annulus 16, thereby clamping walls 21 and 22 respectively against walls 19 and 20 of the groove 15. Just prior to indexing the pressure is released and the inherent resilience of walls 21 and 22 restores them to their normal position in which the walls 19, 20 have a freely rotating or sliding fit with them. The flexible Walls 21 and 22 are preferably of like dimensions so that when fluid pressure is applied to them they exert substantially equal clamping pressures on the opposed walls 19 and 20, so that no appreciable axial load is applied to the spindle and its bearings by the clamping action.

As shown the housing section 11, 23 and 24 are sealed against leakage by flexible O-ring seals 31 and 32. For protecting the clamping surfaces 19, 20, 21 and 22 against the ingress of foreign material a sealing labyrinth 33 with a vent 34 is provided.

The preferred embodiment of the invention having now been described, what is claimed is:

1. A gear cutting machine or the like comprising a spindle housing, a work spindle journaled for rotation in hearings in the housing and having a workpiece-supporting end portion projecting beyond said bearings, said end portion of the spindle having an annular peripheral groove, and the housing having a fluid-expansible tubular annulus fitting in said groove, the opposite side walls of the annulus being adapted for relative displacement, axially of the spindle, to clamp against the opposite walls of the groove upon expansion of the annulus by fluid under pressure.

2. A work holding mechanism comprising a spindle housing assembly, a work spindle assembly rotatable therein, one assembly having a peripheral groove and the other assembly having a fluid-expansible annulus fitting said groove, said annulus comprising spaced relatively flexible side wall portions joined at their outer peripheries to relatively rigid portions of said other assembly and at their inner peripheries having radially spaced telescoping flanges.

3. A work holding mechanism according to claim 2 in which there is an O-ring seal disposed between said flanges. 4. A work holding mechanism according to claim 2 in which said side wall portions are substantially alike in flexibility and eflective area whereby upon fluid expan sionsaid annulus will exert substantially equal pressures against the opposite sides of said groove.

5. A work holding mechanism according to claim 2. in which said other assembly comprises multiple sections and t 3 each of said side wall portions is integral-witha different one of said sections.

6. A machine tool comprising a spindle assemblyhaving a peripheral 'groove therein and a spindle'housingassembly having 'a fluid-expansibleannulus "fitting said groove, said annulus comprising 'relativelytflexibleiop-f posite side walls joined integrally attheirouterperipheries to a rigid portion ofthe housing assembly, said'side walls being adapted for relative flexure' axially of the spindle upon expansion of the annulus to thereby grip the opposite sides of the groove, and afiexiblesealing ring arranged between said side walls adjacent the inner peripheries thereof to accommodate the relative axial displacement of their inner peripheral portions incident to such flexure.

References Cited inthe tile of this patent UNITED STATES PATENTS Jansbli Oct. 30, 1956 

